Dahlen, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.6 °C (low) to 9.4 °C (high). Annual precipitation averages 532.4 Millimeters. Dahlen is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -19.5 °C | -9.9 °C | 13.21 mm |
| February | -17.5 °C | -7.1 °C | 11.94 mm |
| March | -10 °C | -0.2 °C | 18.8 mm |
| April | -1.8 °C | 9.8 °C | 23.37 mm |
| May | 5.6 °C | 18.2 °C | 73.91 mm |
| June | 12 °C | 23.3 °C | 100.58 mm |
| July | 14.2 °C | 25.9 °C | 87.38 mm |
| August | 12.8 °C | 25.6 °C | 69.09 mm |
| September | 7.6 °C | 20.6 °C | 54.1 mm |
| October | 0.2 °C | 11.7 °C | 44.2 mm |
| November | -8 °C | 1.3 °C | 19.56 mm |
| December | -15.3 °C | -6.7 °C | 16.26 mm |
| Annual | -1.6 °C | 9.4 °C | 532.4 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |